Apparatus and method for processing substrate

ABSTRACT

Disclosed is a method for processing a substrate, comprising a liquid processing step of performing liquid processing on the substrate by supplying a processing liquid onto the substrate in a liquid processing chamber, a transfer step of transferring the substrate from the liquid processing chamber to a drying chamber, and a drying step of drying the substrate in the drying chamber. In the drying step, the substrate is dried while an edge region of the substrate other than a central region of the substrate is supported by a support unit, and in the liquid processing step, the liquid processing is performed on the substrate such that a height of the processing liquid remaining on the edge region of the substrate is greater than a height of the processing liquid remaining on the central region of the substrate when the liquid processing is completed in the liquid processing chamber.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. Application Ser.No. 17/026,389, filed on Sep. 21, 2020, and entitled “APPARATUS ANDMETHOD FOR PROCESSING SUBSTRATE”, now pending, which is a continuationapplication of U.S. Pat. Application Ser. No. 16/197,458, filed on Nov.21, 2018, and entitled “APPARATUS AND METHOD FOR PROCESSING SUBSTRATE”,now abandoned. The entire contents of which are hereby incorporated byreference.

BACKGROUND

Embodiments of the inventive concept described herein relate to anapparatus and method for processing a substrate, and more particularly,relate to an apparatus and method for processing a substrate with aliquid supplied onto the substrate and then removing the liquid.

Semiconductor processes comprise a process of cleaning a thin film,foreign matter, particles, or the like on a substrate. The cleaningprocess is performed by placing the substrate on a spin head such that apattern face is directed upward or downward, supplying a processingliquid onto the substrate while rotating the spin head, and drying thesubstrate.

Recently, a supercritical fluid is used in a process of cleaning asubstrate. For example, a liquid processing chamber for performingliquid processing on a substrate by supplying a processing liquid onto asubstrate and a drying chamber for removing the processing liquid fromthe substrate by using a supercritical fluid after the liquid processingare provided, and the substrate completely processed in the liquidprocessing chamber is transferred into the drying chamber by a transferrobot.

FIG. 17 is a view illustrating a drying chamber 1000 for drying asubstrate W using a supercritical fluid. The drying chamber 1000 has asupport unit 1200 therein, which supports the substrate W. The supportunit 1200 supports an edge region of the bottom side of the substrate W.

When a processing liquid is removed from the substrate W, it ispreferable that all the processing liquid be removed from the entireregion of the substrate W by the supercritical fluid. If the processingliquid on the substrate W is removed by natural drying or heating ratherthan the supercritical fluid, a leaning phenomenon arises in whichpatterns lean as shown by “A” of FIG. 18 .

When the substrate W is placed on the support unit 1200 to remove theprocessing liquid on the substrate W by using the drying chamber 1000with the structure illustrated in FIG. 17 , the substrate W sags in themiddle as illustrated in FIG. 19 . Due to the sagging of the substrateW, part of the processing liquid remaining on the edge region of thesubstrate W flows toward the central region of the substrate W. In thiscase, the thickness of the processing liquid on the edge region of thesubstrate W is decreased, and the edge region of the substrate W isnaturally dried before the supercritical fluid is supplied. Furthermore,since a large amount of processing liquid has to be removed from thecentral region of the substrate W, it takes a significant amount of timeto dry the processing liquid. These problems grow bigger with anincrease in the diameter of the substrate W.

The drying chamber 1000 is heated such that the fluid supplied into thedrying chamber 1000 to remove the processing fluid is maintained in asupercritical state. In this case, the temperatures of structures, suchas outer walls of the drying chamber 1000 and the support unit 1200, arehigher than the temperature in the inner space of the drying chamber1000. Therefore, a larger amount of processing liquid is evaporated bythe heating from the edge region of the substrate W brought into contactwith the support unit 1200, and the edge region of the substrate W islikely to be dried by the heating or naturally dried.

In addition, even when a substrate W, the entire bottom side of which issupported, is dried using a supercritical fluid, the following problemsare encountered. When removing a processing liquid from the substrate Wby drying the substrate W after processing the substrate W with theprocessing liquid, it takes a large amount of time to dry the substrateW in the case where a large amount of processing liquid remains on thesubstrate W. If the substrate W is processed using a small amount ofprocessing liquid to reduce drying time, a liquid remaining on thesubstrate W is not sufficiently replaced with the processing liquid.

SUMMARY

Embodiments of the inventive concept provide a substrate processingapparatus and method for improving drying efficiency when drying asubstrate using a supercritical fluid.

Furthermore, embodiments of the inventive concept provide a substrateprocessing apparatus and method for preventing an edge region of asubstrate from being naturally dried.

Moreover, embodiments of the inventive concept provide a substrateprocessing apparatus and method for preventing a large amount of timefrom being taken to remove a processing liquid when drying a substrate.

In addition, embodiments of the inventive concept provide a substrateprocessing apparatus and method for adjusting a level of a processingliquid remaining on a substrate to a set level when the substrate istransferred into a drying chamber from a liquid processing chamber.

Aspects of the inventive concept are not limited thereto, and any otheraspects not mentioned herein will be clearly understood from thefollowing description by those skilled in the art to which the inventiveconcept pertains.

According to an aspect of an embodiment, a method for processing asubstrate comprises a liquid processing step of performing liquidprocessing on the substrate by supplying a processing liquid onto thesubstrate in a liquid processing chamber, a transfer step oftransferring the substrate from the liquid processing chamber to adrying chamber, and a drying step of drying the substrate in the dryingchamber. In the drying step, the substrate is dried while an edge regionof the substrate other than a central region of the substrate issupported by a support unit, and in the liquid processing step, theliquid processing is performed on the substrate such that a height ofthe processing liquid remaining on the edge region of the substrate ishigher than a height of the processing liquid remaining on the centralregion of the substrate when the liquid processing is completed in theliquid processing chamber.

According to an embodiment, the liquid processing step may comprise aliquid supply step in which the substrate is rotated and the processingliquid is supplied toward the substrate and a liquid level adjustmentstep in which the substrate is rotated and the supply of the processingliquid is stopped after the liquid supply step.

According to an embodiment, the substrate may be rotated at a firstspeed in the liquid supply step and at a second speed in the liquidlevel adjustment step, and the second speed may be lower than the firstspeed.

According to an embodiment, the liquid supply step may comprise a firstsupply step in which the substrate is rotated at a first rotating speedand the processing liquid is supplied toward the substrate at a firstflow rate and a second supply step in which the substrate is rotated ata second rotating speed and the processing liquid is supplied toward thesubstrate at a second flow rate. The first rotating speed may be higherthan the second rotating speed, and the first flow rate may be greaterthan the second flow rate.

According to an embodiment, in the liquid processing step, a centralnozzle and an edge nozzle may simultaneously supply the processingliquid onto the substrate. The central nozzle may supply the processingliquid onto the central region of the rotating substrate, and the edgenozzle may supply the processing liquid onto the edge region of therotating substrate. A flow rate of the processing liquid supplied by theedge nozzle may be greater than a flow rate of the processing liquidsupplied by the central nozzle.

According to an embodiment, in the liquid processing step, theprocessing liquid may be supplied onto the rotating substrate through aliquid supply nozzle. A dispensing location of the processing liquidsupplied from the liquid supply nozzle may be moved between the centralregion and the edge region of the substrate. A flow rate of theprocessing liquid supplied onto the edge region of the substrate may bemodified to be greater than a flow rate of the processing liquidsupplied onto the central region of the substrate.

According to an embodiment, in the liquid processing step, the substratemay be processed by sequentially supplying a first liquid, a secondliquid, and a third liquid onto the substrate, and the processing liquidmay be the third liquid. In the drying step, the substrate may be driedusing a supercritical fluid. The third liquid may dissolve better in thesupercritical fluid than the second fluid.

According to an embodiment, the third liquid may comprise isopropylalcohol, and the supercritical fluid may be carbon dioxide.

According to an embodiment, the substrate may be transferred into thedrying chamber, with the processing liquid remaining on the substrate.

According to an embodiment, the first liquid may be an etching fluid,and the second liquid may neutralize the first liquid and may dissolvebetter in the third liquid than the first liquid.

According to an embodiment, the height of the processing liquid on theedge region of the substrate may be higher than the height of theprocessing liquid on the central region of the substrate when thesubstrate is transferred into the drying chamber.

According to an embodiment, the second speed may range from 10 RPM to100 RPM.

According to an embodiment, the first speed may be 200 RPM or more.

According to another aspect of an embodiment, an apparatus forprocessing a substrate comprises a liquid processing chamber thatperforms liquid processing on the substrate by supplying a processingliquid onto the substrate, a drying chamber that removes the processingliquid from the substrate, a transfer unit that transfers the substratebetween the liquid processing chamber and the drying chamber, and acontroller that controls the liquid processing chamber, the dryingchamber, and the transfer unit. The liquid processing chamber comprisesa cup having a processing space inside, a support unit that supports androtate the substrate in the processing space, and a liquid supply unitthat supplies the processing liquid onto the substrate. The dryingchamber comprises a body having an inner space inside, a support thatsupports an edge region of the substrate in the inner space, a fluidsupply unit that supplies a fluid for drying into the inner space, andan exhaust unit that exhausts the fluid in the inner space. Thecontroller controls the liquid processing chamber, the drying chamber,and the transfer unit to sequentially perform a liquid processing stepof performing liquid processing on the substrate by supplying theprocessing liquid onto the substrate in the liquid processing chamber, atransfer step of transferring the substrate from the liquid processingchamber to the drying chamber, and a drying step of drying the substratein the drying chamber and to allow a height of the processing liquidremaining on the edge region of the substrate to be higher than a heightof the processing liquid remaining on a central region of the substratewhen the liquid processing is completed in the liquid processing chamberin the liquid processing step.

According to an embodiment, the controller may control the liquidprocessing chamber such that the liquid processing step comprises aliquid supply step in which the substrate is rotated and the processingliquid is supplied toward the substrate and a liquid level adjustmentstep in which the substrate is rotated and the supply of the processingliquid is stopped after the liquid supply step.

According to an embodiment, the controller may control the liquidprocessing chamber such that a rotating speed of the substrate in theliquid supply step is higher than a rotating speed of the substrate inthe liquid level adjustment step.

According to an embodiment, the liquid supply unit may comprise acentral nozzle that supplies the processing liquid onto the centralregion of the substrate and an edge nozzle that supplies the processingliquid onto the edge region of the substrate. The controller may controlthe liquid processing chamber such that in the liquid supply step, theedge nozzle supplies the processing liquid onto the edge region of therotating substrate at the same time that the central nozzle supplies theprocessing liquid onto the central region of the rotating substrate, anda flow rate of the processing liquid supplied by the edge nozzle isgreater than a flow rate of the processing liquid supplied by thecentral nozzle.

According to an embodiment, in the liquid processing step, the substratemay be processed by sequentially supplying a first liquid, a secondliquid, and a third liquid onto the substrate, and the processing liquidmay be the third liquid. In the drying step, the substrate may be driedusing a supercritical fluid. The third liquid may dissolve better in thesupercritical fluid than the second fluid. The substrate may betransferred into the drying chamber, with the processing liquidremaining on the substrate.

According to another aspect of an embodiment, a method for processing asubstrate comprises a liquid processing process of performing liquidprocessing on the substrate by supplying a processing liquid onto thesubstrate in a liquid processing chamber, a liquid level adjustmentprocess of adjusting a level of the processing liquid remaining on thesubstrate after the liquid processing process, and a drying process ofremoving the processing liquid from the substrate. The liquid leveladjustment process is performed by rotating the substrate while thesupply of the processing liquid onto the substrate is stopped.

According to an embodiment, in the liquid level adjustment process, thelevel of the processing liquid remaining on the substrate may beadjusted by controlling a rotating speed of the substrate.

According to an embodiment, the rotating speed of the substrate in theliquid level adjustment process may be a first set speed when the levelof the processing liquid on the substrate that is set before the dryingprocess is a first level, and the rotating speed of the substrate in theliquid level adjustment process may be a second set speed when the levelof the processing liquid on the substrate that is set before the dryingprocess is a second level. The first level may be higher than the secondlevel, and the first set speed may be lower than the second set speed.

According to an embodiment, the liquid processing process and the liquidlevel adjustment process may be performed in the liquid processingchamber, and the drying process may be performed in a drying chamber.The substrate on which the liquid level adjustment process is completelyperformed in the liquid processing chamber may be transferred into thedrying chamber by a transfer robot.

According to an embodiment, the rotating speed of the substrate in theliquid level adjustment process may be lower than that of the substratein the liquid processing process.

According to an embodiment, in the liquid processing process, thesubstrate may be processed by sequentially supplying a first liquid, asecond liquid, and a third liquid onto the substrate, and the processingliquid may be the third liquid. In the drying step, the substrate may bedried using a supercritical fluid. The third liquid may dissolve betterin the supercritical fluid than the second fluid.

According to an embodiment, a height of the processing liquid on an edgeregion of the substrate may be higher than a height of the processingliquid on a central region of the substrate when the substrate istransferred into the drying chamber.

According to an embodiment of the inventive concept, drying efficiencymay be improved when a substrate is dried using a supercritical fluid.

Furthermore, according to an embodiment of the inventive concept, anedge region of a substrate may be prevented from being naturally driedwhen the substrate is dried.

Moreover, according to an embodiment of the inventive concept, it ispossible to prevent a large amount of time from being taken to remove aprocessing liquid when drying a substrate.

In addition, according to an embodiment of the inventive concept, alevel of a processing liquid remaining on a substrate when the substrateis transferred into a drying chamber from a liquid processing chambermay be set to a set level, thereby improving drying efficiency.

Effects of the inventive concept are not limited to the above-describedeffects, and any other effects not mentioned herein may be clearlyunderstood from this specification and the accompanying drawings bythose skilled in the art to which the inventive concept pertains.

BRIEF DESCRIPTION OF THE FIGURES

The above and other objects and features will become apparent from thefollowing description with reference to the following figures, whereinlike reference numerals refer to like parts throughout the variousfigures unless otherwise specified, and wherein:

FIG. 1 is a schematic plan view illustrating a substrate processingapparatus according to an embodiment of the inventive concept;

FIG. 2 is a schematic view illustrating a liquid processing chamber ofFIG. 1 according to an embodiment of the inventive concept;

FIG. 3 is a schematic view illustrating a drying chamber of FIG. 1according to an embodiment of the inventive concept;

FIG. 4 is a flowchart illustrating a substrate processing methodaccording to an embodiment of the inventive concept;

FIGS. 5 and 6 are views illustrating processing of a substrate in aliquid supply step and a liquid level adjustment step, respectively;

FIG. 7 is a view illustrating an example of a rotating speed of thesubstrate in the liquid supply step;

FIGS. 8 to 11 are views illustrating a variation in the height of aprocessing liquid on a substrate in a liquid supply step, a liquid leveladjustment step, a transfer step, and a drying step, respectively;

FIGS. 12 to 15 are views illustrating various modified examples ofsupplying a processing liquid onto a substrate in the liquid processingchamber;

FIG. 16 is a view illustrating a correlation between a rotating speed ofa substrate in a liquid level adjustment process and the weight of aprocessing liquid remaining on the substrate after adjustment of aliquid level;

FIG. 17 is a view illustrating a general drying chamber for drying asubstrate using a supercritical fluid;

FIG. 18 is a view illustrating a leaning phenomenon that arises on asubstrate during natural drying; and

FIG. 19 is a view illustrating a state of a processing liquid on asubstrate when a drying process is performed in the apparatus of FIG. 17.

DETAILED DESCRIPTION

Hereinafter, embodiments of the inventive concept will be described inmore detail with reference to the accompanying drawings. The inventiveconcept may, however, be embodied in different forms and should not beconstructed as limited to the embodiments set forth herein. Rather,these embodiments are provided so that this disclosure will be thoroughand complete, and will fully convey the scope of the inventive conceptto those skilled in the art. In the drawings, the dimensions of elementsare exaggerated for clarity of illustration.

FIG. 1 is a schematic plan view illustrating a substrate processingapparatus according to an embodiment of the inventive concept.

Referring to FIG. 1 , the substrate processing apparatus may comprise anindex module 10, a processing module 20, and a controller(not shown).According to an embodiment, the index module 10 and the processingmodule 20 may be arranged in one direction. Hereinafter, the directionin which the index module 10 and the processing module 20 are arrangedmay be referred to as a first direction 92, a direction perpendicular tothe first direction 92 when viewed from above may be referred to as asecond direction 94, and a direction perpendicular to both the firstdirection 92 and the second direction 94 may be referred to as a thirddirection 96.

The index module 10 may transfer substrates W in containers 80 to theprocessing module 20 and may place the substrates W completely processedin the processing module 20 in the containers 80. The longitudinaldirection of the index module 10 may be oriented in the second direction94. The index module 10 may have a plurality of load ports 12 and anindex frame 14. The load ports 12 may be located on the opposite side tothe processing module 20 with respect to the index frame 14. Thecontainers 80 having the substrates W received therein may be placed onthe load ports 12. The plurality of load ports 12 may be arranged alongthe second direction 94.

Airtight containers, such as front open unified pods (FOUPs), may beused as the containers 80. The containers 80 may be placed on the loadports 12 by a transfer means (not illustrated), such as an overheadtransfer, an overhead conveyor, or an automatic guided vehicle, or aworker.

The index frame 14 may have an index robot 120 inside. A guide rail 140may be provided in the index frame 14. The longitudinal direction of theguide rail 140 may be oriented in the second direction 94. The indexrobot 120 may be provided on the guide rail 140 so as to be movablealong the guide rail 140. The index robot 120 may comprise a pluralityof hands 122 on which the substrates W are placed. The hands 122 maymove forward or backward, may rotate about an axis oriented in the thirddirection 96, or may move along the third direction 96. The plurality ofhands 122 may be spaced apart from each other in the vertical directionand may independently move forward or backward.

The processing module 20 may comprise a buffer unit 200, a transferchamber 300, liquid processing chambers 400, and drying chambers 500.The buffer unit 200 may provide a space in which substrates W to beloaded into the processing module 20 and substrates W unloaded from theprocessing module 20 temporarily stay. The liquid processing chambers400 may perform liquid processing on a substrate W by supplying a liquidonto the substrate W. The drying chambers 500 may remove the liquidremaining on the substrate W. The transfer chamber 300 transferssubstrates W between the buffer unit 200, the liquid processing chambers400, and the drying chambers 500.

The transfer chamber 300 may be arranged such that the longitudinaldirection thereof is oriented in the first direction 92. The buffer unit200 may be disposed between the index module 10 and the transfer chamber300. The liquid processing chambers 400 and the drying chambers 500 maybe disposed on lateral sides of the transfer chamber 300. The liquidprocessing chambers 400 and the transfer chamber 300 may be arrangedalong the second direction 94. The drying chambers 500 and the transferchamber 300 may be arranged along the second direction 94. The bufferunit 200 may be located at one end of the transfer chamber 300.

According to an embodiment, the liquid processing chambers 400 may bedisposed on the opposite lateral sides of the transfer chamber 300. Thedrying chambers 500 may be disposed on the opposite lateral sides of thetransfer chamber 300. The liquid processing chambers 400 may be disposedto be closer to the buffer unit 200 than the drying chambers 500. Theliquid processing chambers 400 may be arranged in an A x B array (A andB being natural numbers of 1 or larger) on one lateral side of thetransfer chamber 300 along the first and third directions 92 and 96.Furthermore, the drying chambers 500 may be arranged in a C x D array (Cand D being natural numbers of 1 or larger) on the one lateral side ofthe transfer chamber 300 along the first and third directions 92 and 96.Alternatively, only the liquid processing chambers 400 may be arrangedon the one lateral side of the transfer chamber 300, and the dryingchambers 500 may be arranged on the opposite lateral side of thetransfer chamber 300.

The transfer chamber 300 may have a transfer robot 320 inside. A guiderail 340 may be provided in the transfer chamber 300. The longitudinaldirection of the guide rail 340 may be oriented in the first direction92. The transfer robot 320 may be provided on the guide rail 340 so asto be movable along the guide rail 340. The transfer robot 320 maycomprise a plurality of hands 322 on which substrates W are placed. Thehands 322 may move forward or backward, may rotate about an axisoriented in the third direction 96, or may move along the thirddirection 96. The plurality of hands 322 may be spaced apart from eachother in the vertical direction and may independently move forward orbackward.

The buffer unit 200 may comprise a plurality of buffers 220 in whichsubstrates W are placed. The buffers 220 may be spaced apart from eachother along the third direction 96. The buffer unit 200 may be open atthe front side and the rear side thereof. The front side may face theindex module 10, and the rear side may face the transfer chamber 300.The index robot 120 may approach the buffer unit 200 through the openfront side thereof, and the transfer robot 320 may approach the bufferunit 200 through the open rear side thereof.

FIG. 2 is a schematic view illustrating the liquid processing chamber400 of FIG. 1 according to an embodiment of the inventive concept.Referring to FIG. 2 , the liquid processing chamber 400 may have ahousing 410, a cup 420, a support unit 440, a liquid supply unit 460,and a lifting unit 480. The housing 410 may have a substantiallyrectangular parallelepiped shape. The cup 420, the support unit 440, andthe liquid supply unit 460 may be disposed inside the housing 410.

The cup 420 may have a processing space that is open at the top, and asubstrate W may be processed with liquids in the processing space. Thesupport unit 440 may support the substrate W in the processing space.The liquid supply unit 460 may supply the liquids onto the substrate Wsupported on the support unit 440. The liquids may be sequentiallysupplied onto the substrate W. The lifting unit 480 may adjust theheight of the cup 420 relative to the support unit 440.

According to an embodiment, the cup 420 may have a plurality ofcollection bowls 422, 424, and 426. The collection bowls 422, 424, and426 may have collection spaces for collecting the liquids used toprocess the substrate W, respectively. Each of the collection bowls 422,424, and 426 may have a ring shape surrounding the support unit 440. Theprocessing liquids scattered by rotation of the substrate W duringliquid processing may be introduced into the collection spaces throughinlets 422 a, 424 a, and 426 a of the respective collection bowls 422,424, and 426. According to an embodiment, the cup 420 may have the firstcollection bowl 422, the second collection bowl 424, and the thirdcollection bowl 426. The first collection bowl 422 may be disposed tosurround the support unit 440, the second collection bowl 424 may bedisposed to surround the first collection bowl 422, and the thirdcollection bowl 426 may be disposed to surround the second collectionbowl 424. The second inlet 424 a through which a liquid is introducedinto the second collection bowl 424 may be located above the first inlet422 a through which a liquid is introduced into the first collectionbowl 422. The third inlet 426 a through which a liquid is introducedinto the third collection bowl 426 may be located above the second inlet424 a.

The support unit 440 may have a support plate 442 and a driving shaft444. The top side of the support plate 442 may have a substantiallycircular shape and may have a larger diameter than the substrate W.Support pins 442 a may be provided on the central portion of the supportplate 442 to support the bottom side of the substrate W. The supportpins 442 a may protrude upward from the support plate 442 such that thesubstrate W is spaced apart from the support plate 442 by apredetermined distance. Chuck pins 442 b may be provided on the edgeportion of the support plate 442. The chuck pins 442 b may protrudeupward from the support plate 442 and may support the lateral portion ofthe substrate W to prevent the substrate W from being separated from thesupport unit 440 when being rotated. The driving shaft 444 may be drivenby an actuator 446. The driving shaft 444 may be connected to the centerof the bottom side of the support plate 442 and may allow the supportplate 442 to rotate about its axis.

According to an embodiment, the liquid supply unit 460 may have a firstnozzle 462, a second nozzle 464, and a third nozzle 466. The firstnozzle 462 may supply a first liquid onto the substrate W. The firstliquid may be a liquid for removing a film or foreign matter remainingon the substrate W. The second nozzle 464 may supply a second liquidonto the substrate W. The second liquid may be a liquid that dissolveswell in a third liquid. For example, the second liquid may be a liquidthat dissolves better in the third liquid than the first liquid. Thesecond liquid may be a liquid that neutralizes the first liquid suppliedonto the substrate W. Furthermore, the second liquid may be a liquidthat neutralizes the first liquid and dissolves better in the thirdliquid than the first liquid. According to an embodiment, the secondliquid may be water. The third nozzle 466 may supply the third liquidonto the substrate W. The third liquid may be a liquid that dissolveswell in a supercritical fluid that is used in the drying chambers 500.For example, the third liquid may be a liquid that dissolves better inthe supercritical fluid used in the drying chambers 500 than the secondliquid. According to an embodiment, the third liquid may be an organicsolvent. The organic solvent may be isopropyl alcohol. The first nozzle462, the second nozzle 464, and the third nozzle 466 may be supported bydifferent arms 461. The arms 461 may be independently moved.Alternatively, the first nozzle 462, the second nozzle 464, and thethird nozzle 466 may be mounted on and simultaneously moved by the samearm.

The lifting unit 480 may vertically move the cup 420. The height of thecup 420 relative to the substrate W may be modified by the verticalmovement of the cup 420. Accordingly, the collection bowls 422, 424, and426 for collecting the processing liquids may be changed depending onthe types of liquids supplied onto the substrate W, thereby separatelycollecting the liquids. Alternatively, the cup 420 may be fixed, and thelifting unit 480 may vertically move the support unit 440.

FIG. 3 is a schematic view illustrating the drying chamber 500 of FIG. 1according to an embodiment of the inventive concept. According to anembodiment, the drying chamber 500 may remove a liquid on a substrate Wusing a supercritical fluid. The drying chamber 500 may have a body 520,a support 540, a fluid supply unit 560, and a blocking plate 580.

The body 520 may have an inner space 502 in which a drying process isperformed. The body 520 may have an upper body 522 and a lower body 524.The upper body 522 and the lower body 524 may be combined together toprovide the above-described inner space 502. The upper body 522 may beprovided above the lower body 524. The upper body 522 may be fixed inone position, and the lower body 524 may be vertically moved by adriving member 590 such as a cylinder. When the lower body 524 isseparated from the upper body 522, the inner space 502 may be opened,and the substrate W may be placed in or retrieved from the inner space502. During the drying process, the lower body 524 may be brought intoclose contact with the upper body 522, and therefore the inner space 502may be hermetically sealed from the outside. The drying chamber 500 mayhave a heater 570. According to an embodiment, the heater 570 may belocated in a wall of the body 520. The heater 570 may heat the innerspace 502 of the body 520 such that a fluid supplied into the innerspace 502 of the body 520 is maintained in a supercritical state.

The support 540 may support the substrate W in the inner space 502 ofthe body 520. The support 540 may have fixed rods 542 and support parts544. The fixed rods 542 may be fixedly installed on the upper body 522to protrude downward from the bottom side of the upper body 522. Thelongitudinal direction of the fixed rods 542 may be oriented in thevertical direction. The plurality of fixed rods 542 may be spaced apartfrom each other. The fixed rods 542 may be arranged such that thesubstrate W does not interfere with the fixed rods 542 when being placedin or retrieved from the space surrounded by the fixed rods 542. Thesupport parts 544 may be coupled to the respective fixed rods 542. Thesupport parts 544 may extend from lower ends of the fixed rods 542toward the space surrounded by the fixed rods 542. Due to theabove-described structure, the edge region of the substrate W placed inthe inner space 502 of the body 520 may be placed on the support parts544, and the entire top side of the substrate W, the central region ofthe bottom side of the substrate W, and part of the edge region of thebottom side of the substrate W may be exposed to a fluid for drying thatis supplied into the inner space 502.

The fluid supply unit 560 may supply the fluid for drying into the innerspace 502 of the body 520. According to an embodiment, the fluid fordrying may be supplied into the inner space 502 in a supercriticalstate. Alternatively, the fluid for drying may be supplied into theinner space 502 in a gaseous state and may experience a phase changeinto a supercritical state in the inner space 502. According to anembodiment, the fluid supply unit 560 may have a main supply line 562,an upper branch line 564, and a lower branch line 566. The upper branchline 564 and the lower branch line 566 may branch from the main supplyline 562. The upper branch line 564 may be coupled to the upper body 522and may supply the fluid for drying from above the substrate W placed onthe support 540. According to an embodiment, the upper branch line 564may be coupled to the center of the upper body 522. The lower branchline 566 may be coupled to the lower body 524 and may supply the fluidfor drying from below the substrate W placed on the support 540.According to an embodiment, the lower branch line 566 may be coupled tothe center of the lower body 524. An exhaust line 550 may be coupled tothe lower body 524. The supercritical fluid in the inner space 502 ofthe body 520 may be exhausted outside the body 520 through the exhaustline 550.

The blocking plate 580 may be disposed in the inner space 502 of thebody 520. The blocking plate 580 may have a circular plate shape. Theblocking plate 580 may be supported by support rods 582 so as to bespaced apart upward from the bottom of the body 520. The plurality ofsupport rods 582 may have a rod shape and may be spaced apart from eachother by a predetermined distance. When viewed from above, the blockingplate 580 may be superimposed on an outlet of the lower branch line 566and an inlet of the exhaust line 550. The blocking plate 580 may preventthe fluid for drying, which is supplied through the lower branch line566, from being directly sprayed toward the substrate W to damage thesubstrate W.

The controller(not shown) may control the transfer robot 320, the liquidprocessing chambers 400, and the drying chambers 500 to processsubstrates W by a preset substrate processing method. Hereinafter, anexample of the substrate processing method will be described.

FIG. 4 is a flowchart illustrating a substrate processing methodaccording to an embodiment of the inventive concept. Referring to FIG. 4, the substrate processing method may comprise liquid processing stepS100, transfer step S200, and drying step S300.

Liquid processing step S100 may be performed in the liquid processingchamber 400. In liquid processing step S100, liquids may be suppliedonto a substrate W to process the substrate W. According to anembodiment, in liquid processing step S100, a first liquid, a secondliquid, and a third liquid may be sequentially supplied onto thesubstrate W to process the substrate W. The first liquid may be achemical containing an acid or alkali, such as a sulfuric acid, a nitricacid, a hydrochloric acid, or the like. The second liquid may be purewater, and the third liquid may be isopropyl alcohol. First, thechemical may be supplied onto the substrate W to remove a thin film orforeign matter remaining on the substrate W. Next, the pure water may besupplied onto the substrate W, and the chemical on the substrate W maybe replaced with the pure water. Then, the isopropyl alcohol may besupplied onto the substrate W, and the pure water on the substrate W maybe replaced with the isopropyl alcohol. Since the pure water dissolvesbetter in the isopropyl alcohol than the chemical, the pure water may beeasy to replace. Furthermore, the surface of the substrate W may beneutralized by the pure water. Since the isopropyl alcohol dissolveswell in carbon dioxide used in the drying chamber 500, the isopropylalcohol may be easily removed by the carbon dioxide in a supercriticalstate in the drying chamber 500.

Transfer step S200 may be performed by the transfer robot 320. After theliquid processing is completed in the liquid processing chamber 400,transfer step S200 of transferring the substrate W into the dryingchamber 500 from the liquid processing chamber 400 may be performed.While the substrate W is being transferred by the transfer robot 320, aliquid may remain on the substrate W. Hereinafter, the liquid remainingon the substrate W during the transfer of the substrate W by thetransfer robot 320 may be referred to as the processing liquid. In theabove-described embodiment, the processing liquid may be, for example,the third liquid.

Drying step S300 may be performed in the drying chamber 500. Thesubstrate W transferred into the drying chamber 500 may be supported bythe support 540, with the edge region of the substrate W placed on thesupport parts 544. Carbon dioxide may be supplied into the inner space502 of the body 520 through the lower branch line 566. When the pressureinside the inner space 502 of the body 520 reaches a set pressure,carbon dioxide may be supplied into the inner space 502 of the body 520through the upper branch line 564. Alternatively, when the pressureinside the inner space 502 of the body 520 reaches the set pressure,carbon dioxide may be simultaneously supplied into the inner space 502of the body 520 through the upper branch line 564 and the lower branchline 566. During the process, the carbon dioxide may be periodicallysupplied into or discharged from the inner space 502 of the body 520 aplurality of times. When a predetermined amount of the processing liquidremaining on the substrate W is dissolved in the supercritical carbondioxide by the above-described method, the carbon dioxide may bedischarged from the inner space 502, and new carbon dioxide may besupplied into the inner space 502, thereby improving the rate of removalof the processing liquid from the substrate W.

Next, a process of processing the substrate W with the processing liquidin the liquid processing chamber 400 will be described in detail. In anembodiment described below, the processing liquid may be an organicsolvent such as isopropyl alcohol.

When liquid processing step S100 is completed in the liquid processingchamber 400, the height of the processing liquid remaining on the edgeregion of the substrate W may be higher than the height of theprocessing liquid remaining on the central region of the substrate W.According to an embodiment, liquid processing step S100 may compriseliquid supply step S110 and liquid level adjustment step S120.

FIGS. 5 and 6 are views illustrating processing of the substrate W inliquid supply step S110 and liquid level adjustment step S120,respectively.

Referring to FIG. 5 , in liquid supply step S110, the processing liquidmay be supplied onto the substrate W. In liquid supply step S110, thesubstrate W may be rotated at a first speed of V1. The processing liquidmay be supplied onto the central region of the substrate W. For example,the processing liquid may be supplied toward the center of the substrateW.

In liquid level adjustment step S120, the thickness of the processingliquid supplied onto the substrate W may be adjusted. According to anembodiment, in liquid level adjustment step S120, the thickness of theprocessing liquid may be adjusted to vary depending on regions on thesubstrate W. For example, the thickness of the processing liquid may beadjusted such that the thickness of the processing liquid on the edgeregion of the substrate W is greater than the thickness of theprocessing liquid on the central region of the substrate W. Referring toFIG. 6 , in liquid level adjustment step S120, the supply of theprocessing liquid onto the substrate W may be stopped, and the substrateW may be rotated at a second speed of V2. The thickness of theprocessing liquid may be adjusted by controlling the second speed V2.

FIG. 7 is a view illustrating an example of a rotating speed of thesubstrate W in liquid supply step S110. Referring to FIG. 7 , the secondspeed V2 in liquid level adjustment step S120 may be lower than thefirst speed V1 in liquid supply step S110. The second speed V2appropriate for the thicknesses of the processing liquid that arerequired for the edge region and the central region of the substrate Wmay be determined by conducting a test by modifying the RPM of thesubstrate W in liquid level adjustment step S120. According to anembodiment, the first speed V1 in liquid supply step S110 may be 200 RPMor more, and the second speed V2 in liquid level adjustment step S120may range from 10 RPM to 100 RPM. When liquid level adjustment step S120is completed, the rotation of the substrate W may be stopped.

Hereinafter, a variation in the height of the processing liquid on thesubstrate W in liquid supply step S110, liquid level adjustment stepS120, transfer step S200, and drying step S300 will be described withreference to FIGS. 8 to 11 . FIG. 8 is a view illustrating an example ofthe thickness of the processing liquid on the substrate W when liquidsupply step S110 is completed, and FIG. 9 is a view illustrating anexample of the thickness of the processing liquid on the substrate Wwhen liquid level adjustment step S120 is completed. FIG. 10 is a viewillustrating an example of the thickness of the processing liquid on thesubstrate W when the substrate W is transferred into the drying chamber500, and FIG. 11 is a view illustrating an example of the thickness ofthe processing liquid on the substrate W when the substrate W is placedon the support 540 of the drying chamber 500.

When liquid supply step S110 is completed in FIG. 7 , the thickness h1of the processing liquid on the entire region of the substrate W may besubstantially uniform as illustrated in FIG. 8 , or the thickness of theprocessing liquid on the central region of the substrate W may beslightly greater than the thickness of the processing liquid on the edgeregion of the substrate W. Thereafter, when the substrate W is rotatedat a relatively low speed in liquid level adjustment step S120, theprocessing liquid supplied onto the substrate W may remain in a largeamount on the edge region of the substrate W without being separatedfrom the substrate W by a centrifugal force. Accordingly, as illustratedin FIG. 9 , the height h2 of the processing liquid on the edge region ofthe substrate W may be higher than the height h3 of the processingliquid on the central region of the substrate W.

While the substrate W is being transferred by the transfer robot 320,part of the processing liquid remaining on the edge region of thesubstrate W, as illustrated in FIG. 10 , may flow toward the centralregion of the substrate W due to a restoring force or surface tension.Therefore, immediately after the substrate W is transferred into thedrying chamber 500, the difference in the height of the processingliquid between the edge region and the central region of the substrate Wmay be smaller than that in FIG. 9 although the height h4 of theprocessing liquid on the edge region of the substrate W is maintained tobe greater than the height h5 of the processing liquid on the centralregion of the substrate W.

Thereafter, when the substrate W is placed on the support 540 of thedrying chamber 500, the substrate W, as illustrated in FIG. 11 , may sagin the middle, and part of the processing fluid on the edge region ofthe substrate W may flow to the central region of the substrate W.Furthermore, since the edge region of the substrate W is placed on theheated support parts 544, part of the processing liquid on the edgeregion of the substrate W may evaporate. Due to this, the height h6 ofthe processing liquid on the edge region of the substrate W may bemaintained to be equal to the height of the processing liquid on thecentral region of the substrate W, or the difference in the height ofthe processing liquid between the edge region and the central region ofthe substrate W may be smaller than that in FIGS. 9 or 10 .

According to an embodiment of the inventive concept, since liquid leveladjustment step S120 of rotating the substrate W for a predeterminedperiod of time in the state in which the supply of the processing liquidis stopped is performed after the completion of liquid supply step S110,the thickness of the processing liquid on the edge region of thesubstrate W may be made greater than the thickness of the processingliquid on the central region of the substrate W. Due to this, when thesubstrate W is transferred into the drying chamber 500, the thickness ofthe processing liquid on the edge region of the substrate W may begreater than the thickness of the processing liquid on the centralregion of the substrate W. Although the substrate W, when transferredinto the drying chamber 500 and placed on the support parts 544, sags inthe middle so that part of the processing liquid on the edge region ofthe substrate W flows toward the central region thereof, the processingliquid of a predetermined height may remain on the edge region of thesubstrate W. Accordingly, the edge region of the substrate W may beprevented from being naturally dried. Furthermore, when the substrate Wis placed on the support parts 544 in the drying chamber 500, thedifference in the height of the processing liquid between the edgeregion and the central region of the substrate W may be reduced so thatthe entire region of the substrate W may be uniformly dried by asupercritical fluid.

Next, various modified examples of supplying a processing liquid onto asubstrate in the liquid processing chamber 400 will be described withreference to FIGS. 12 to 15 .

FIG. 12 is a flowchart illustrating a substrate processing methodaccording to an embodiment of the inventive concept. Referring to FIG.12 , a step of supplying a processing liquid onto a substrate W maycomprise liquid supply step S110, transfer step S200, and drying stepS300 as in the embodiment of FIG. 4 . However, liquid supply step S110in the embodiment of the inventive concept may comprise first supplystep S112 and second supply step S114. In first and second supply stepsS112 and S114, the processing liquid may be supplied onto the centralregion of the substrate W. For example, the processing liquid may besupplied to the center of the substrate W. In first supply step S112,the substrate W may be rotated at a first rotating speed of V11, and theprocessing liquid may be supplied onto the substrate W at a first flowrate of Q11. In second supply step S114, the substrate W may be rotatedat a second rotating speed, and the processing liquid may be suppliedonto the substrate W at a second flow rate. The first rotating speed maybe higher than the second rotating speed. Furthermore, the first flowrate may be greater than the second flow rate. In addition, the firstrotating speed may be higher than the second rotating speed, and thefirst flow rate may be greater than the second flow rate. Both the firstrotating speed and the second rotating speed may be higher than a secondspeed in liquid level adjustment step S120.

FIGS. 13 and 14 are schematic views illustrating another example of thesubstrate processing method. FIG. 13 illustrates a first supply step,and FIG. 14 illustrates a second supply step. Referring to FIGS. 13 and14 , a step of performing liquid processing on a substrate W by using aprocessing liquid may comprise a liquid supply step. In the liquidsupply step, the substrate W may be rotated, and the processing liquidmay be supplied onto the substrate . The liquid supply step may comprisethe first supply step and the second supply step. The first supply stepand the second supply step may be sequentially performed. Referring toFIG. 13 , in the first supply step, the processing liquid may besupplied onto the central region of the substrate W. According to anembodiment, the processing liquid may be supplied to the center of thesubstrate W. In the first supply step, the processing liquid may besupplied at a first flow rate of Q11. Referring to FIG. 14 , in thesecond supply step, the processing liquid may be supplied onto the edgeregion of the substrate W. In the second supply step, the processingliquid may be supplied at a second flow rate of Q12. According to anembodiment, the first flow rate Q11 may be less than the second flowrate Q12. The rotating speed of the substrate W in the first supply stepmay differ from the rotating speed of the substrate W in the secondsupply step. For example, the rotating speed of the substrate W in thesecond supply step may be lower than the rotating speed of the substrateW in the first supply step.

According to an embodiment, during the supply of the processing fluid,the third nozzle 466 may be moved to modify the location where theprocessing liquid is supplied onto the substrate W. The location wherethe processing liquid is supplied may be continuously shifted from thecenter of the substrate W to an end portion thereof. Alternatively, thelocation where the processing liquid is supplied may be fixed in aspecific position of the central region of the substrate W and may thenbe fixed in a specific position of the edge region of the substrate W.When the substrate W is completely processed with the processing liquidby the above-described method, the thickness of the processing liquid onthe edge region of the substrate W may be maintained to be greater thanthe thickness of the processing liquid on the central region of thesubstrate W. The flow rates of the processing fluid supplied onto thecentral region and the edge region of the substrate W may be determinedto be appropriate for the thicknesses of the processing liquid that arerequired for the central region and the edge region of the substrate W,by conducting a test by modifying the flow rate of the processing liquidin each region.

FIG. 15 is a schematic view illustrating another example of thesubstrate processing method. Referring to FIG. 15 , the third nozzle 466for supplying a processing liquid onto a substrate W may comprise acentral nozzle 466 a and an edge nozzle 466 b. The central nozzle 466 amay supply the processing liquid onto the central region of thesubstrate W, and the edge nozzle 466 b may supply the processing liquidonto the edge region of the substrate W. The central nozzle 466 a andthe edge nozzle 466 b may be mounted on the arm 461 and may be operatedtogether. Alternatively, the central nozzle 466 a and the edge nozzle466 b may be mounted on different arms 461 and may be separatelyoperated. Referring to FIG. 15 , a step of performing liquid processingon the substrate W by using the processing liquid may comprise a liquidsupply step. In the liquid supply step, the substrate W may be rotated,and the processing liquid may be supplied onto the substrate W. In theliquid supply step, the processing liquid may be simultaneously suppliedonto the substrate W through the central nozzle 466 a and the edgenozzle 466 b. The flow rate Q22 of the processing liquid supplied by theedge nozzle 466 b may be greater than the flow rate Q21 of theprocessing liquid supplied by the central nozzle 466 a. When thesubstrate W is completely processed with the processing liquid by theabove-described method, the thickness of the processing liquid on theedge region of the substrate W may be maintained to be greater than thethickness of the processing liquid on the central region of thesubstrate W. The flow rates of the processing fluid supplied onto thecentral region and the edge region of the substrate W may be determinedto be appropriate for the thicknesses of the processing liquid that arerequired for the central region and the edge region of the substrate W,by conducting a test by modifying the flow rates of the processingliquid supplied by the central nozzle 466 a and the edge nozzle 466 b.

In the embodiment of FIGS. 13 and 14 and the embodiment of FIG. 15 , thethicknesses of the processing liquid on the central region and the edgeregion of the substrate W may be adjusted by only the liquid supply stepwithout a step of stopping the supply of the processing liquid. In theembodiment of FIGS. 13 and 14 and the embodiment of FIG. 15 , a step ofstopping the supply of the processing liquid and rotating the substrateW may be additionally performed after the liquid supply step.

According to another embodiment of the inventive concept, a substrateprocessing method may comprise liquid processing process S500, liquidlevel adjustment process S600, and a drying process.

In liquid processing process S500, liquids may be supplied onto asubstrate W to process the substrate W. According to an embodiment, inliquid processing process S500, a first liquid, a second liquid, and athird liquid may be sequentially supplied onto the rotating substrate Wto process the substrate W. The first to third liquids may be the sametype as those in the above-described embodiments. In the embodiment ofthe inventive concept, the third liquid may be a liquid that is lastsupplied onto the substrate W in liquid processing process S500, and aprocessing liquid may correspond to the third liquid.

Liquid level adjustment process S600 may be performed after liquidprocessing process S500 is completed. In liquid level adjustment processS600, the level of the processing liquid remaining on the substrate Wmay be adjusted. In liquid level adjustment process S600, the substrateW may be rotated in the state in which the supply of the processingliquid onto the substrate W is stopped. In liquid level adjustmentprocess S600, the level of the processing liquid remaining on thesubstrate W may be adjusted by controlling the rotating speed of thesubstrate W.

FIG. 16 is a view illustrating a correlation between the rotating speedof the substrate W in the liquid level adjustment process and the weightof the processing liquid remaining on the substrate W after theadjustment of the liquid level. Referring to FIG. 16 , the weight of theprocessing liquid on the substrate W was measured by changing therotating speed of the substrate W to V21, V22, and V23 in liquid leveladjustment process S600, and the weight of the processing liquid on thesubstrate W was measured to be a, b, and c. The rotating speed of thesubstrate W was reduced in the order of V21, V22, and V23, and themeasured weight of the processing liquid was increased in the order a,b, and c.

According to the embodiment of the inventive concept, the rotating speedof the substrate W in liquid level adjustment process S600 may be set toa first set speed in the case where the level of the processing liquidremaining on the substrate W before the drying process is set to a firstlevel, and may be set to a second set speed in the case where the levelof the processing liquid remaining on the substrate W before the dryingprocess is set to a second level. When the first level is higher thanthe second level, the first set speed may be lower than the second setspeed. The rotating speed of the substrate W may be determined such thatthe level of the processing liquid remaining on the substrate W afterliquid processing process S500 reaches a preset level, by conducting atest by changing the RPM of the substrate W in liquid level adjustmentprocess S600.

The drying process may be performed after liquid level adjustmentprocess S600 is completed. In the drying process, the processing liquidremaining on the substrate W may be removed.

According to the embodiment of the inventive concept, liquid processingprocess S500 may be performed in the liquid processing chamber 400 ofFIG. 1 , and the drying process may be performed in the drying chamber500. The liquid processing chamber 400 and the drying chamber 500 may beprovided in the same manner as described above with regard to theembodiments, and the substrate W on which liquid processing process S500is completely performed in the liquid processing chamber 400 may betransferred into the drying chamber 500 by the transfer robot 320. Inthe embodiment of the inventive concept, the drying chamber 500 may havea structure that supports the entire bottom side of the substrate W.Alternatively, the drying chamber 500 may support only the centralregion of the substrate W. In another case, the drying chamber 500 maysupport the substrate W in various ways. A fluid for drying that is usedin the drying chamber 500 may be the same as those in theabove-described embodiments.

While the inventive concept has been described with reference toembodiments, it will be apparent to those skilled in the art thatvarious changes and modifications may be made without departing from thespirit and scope of the inventive concept. Therefore, it should beunderstood that the above embodiments are not limiting, butillustrative.

What is claimed is:
 1. A method for processing a substrate, the methodcomprising: a liquid processing step for performing liquid processing onthe substrate by supplying a processing liquid onto the substrate; adrying step for drying the substrate after the liquid processing step;wherein the liquid processing step comprises: a liquid supply step forsupplying the processing liquid toward the substrate; and a liquid leveladjustment step for stopping supplying the processing liquid androtating the substrate after the liquid supply step, wherein the liquidsupply step comprises: a first supply step for rotating the substrateand supplying the processing liquid toward the substrate; and a secondsupply step for rotating the substrate and supplying the processingliquid onto an edge region of the substrate after the first supply step.2. The method of claim 1, further comprising a transfer step fortransferring the substrate from a liquid processing chamber to a dryingchamber after the liquid supply step, wherein the liquid processing stepis performed in the liquid processing chamber and the drying step isperformed in the drying chamber.
 3. The method of claim 2, wherein theprocessing liquid comprises an organic solvent.
 4. The method of claim2, wherein in the drying step, the substrate is dried using asupercritical fluid.
 5. The method of claim 2, wherein in the dryingstep, the substrate is dried while the edge region of the substrateexcluding the central region of the substrate is supported by a supportunit.